MyCloud 3TB won't play itunes

Just set up my WDCloud 3TB. Transferred all my iTunes library and photos. Can see photos on all devices, but cannot play iTunes from the NAS at all.
Any ideas?
Also, my Bose Soundtouch20 locates the NAS but won’t find all my songs.
Can anyone help?
I bought the NAS specifically for iTunes!

What app or program are you using to try and play media from the NAS? In iTunes did you change the Library location to the My Cloud iTunes location where you copied the iTunes library?

http://www.macworld.com/article/2996002/streaming-media/how-to-set-up-an-itunes-library-on-a-network-attached-server.html

Have you enabled iTunes and DLNA media server through the My Cloud Dashboard > Settings? Have you enabled Media Serving on the Share holding the iTunes library you copied to the My Cloud? See the My Cloud Dashboard > Shares section to enable Media Serving on Shares.

Many thanks.
How do I access my dashboard?

https://support.wdc.com/knowledgebase/answer.aspx?ID=13965

If you haven’t done so already, you may also want to read through the My Cloud User Manual (https://support.wdc.com/product.aspx?ID=904) to learn more about the My Cloud and how to use/configure the various features of the device.

Hello,
I have checked all the things you suggested. My entire iTunes library is now on the NAS, but when I access the NAS music via the BOSE app, a lot of the songs are missing, and a lot are duplicated.
So, for example, when I access the songs on my phone via the My Cloud App, none of them play.
When I access the NAS playlist list on Bose, a lot are missing and a lot are duplicated.
Can you assist please?
Regards
Nick

How does the Boise app or the Bose device access the My Cloud? Does it use DLNA or some other method?

Do you see the same issue of songs missing, duplicated, etc. when using a DLNA client on your computer or mobile device (like BubbleUPnP for Android)?

If your Boise device uses DLNA to access the My Cloud make sure to read the following unofficial FAQ.

https://community.wd.com/t/faq-twonky-dlna-media-server-setup-use/95373

Depending on how the Boise device accesses and reads the media files you may need to use a metadata tagger/editor (like Media Monkey or MP3Tag) to fill in or correct any metadata tag errors iTunes made when generating/cataloging the media files.